[openib-general] ibv_cmd_create_qp() question

[Roland Dreier]

    Steve> Hey Roland, Why don't I use the same scheme as Heiko for
    Steve> now.  Then I won't hold up the release.  At this point, I
    Steve> can't say for sure what else we might suggest to change in
    Steve> the core APIs anyway.  I'll submit a patch down the road to
    Steve> fix the core to handle this ala create_cq(), but it can
    Steve> wait until 1.1.0.

Actually I'd rather get this straightened out sooner rather than
later.  I don't want ehca merged with the scheme it uses, so I think
libibverbs needs to be ready to do it properly too.

It's pretty trivial to update ibv_cmd_create_qp(); in fact I just did
it.  How does this patch look to you?  (driver library changes coming
shortly)

 - R.

Index: libibverbs/include/infiniband/driver.h
===================================================================
--- libibverbs/include/infiniband/driver.h	(revision 5421)
+++ libibverbs/include/infiniband/driver.h	(working copy)
@@ -114,7 +114,8 @@ int ibv_cmd_destroy_srq(struct ibv_srq *
 
 int ibv_cmd_create_qp(struct ibv_pd *pd,
 		      struct ibv_qp *qp, struct ibv_qp_init_attr *attr,
-		      struct ibv_create_qp *cmd, size_t cmd_size);
+		      struct ibv_create_qp *cmd, size_t cmd_size,
+		      struct ibv_create_qp_resp *resp, size_t resp_size);
 int ibv_cmd_query_qp(struct ibv_qp *qp, struct ibv_qp_attr *qp_attr,
 		     enum ibv_qp_attr_mask attr_mask,
 		     struct ibv_qp_init_attr *qp_init_attr,
Index: libibverbs/ChangeLog
===================================================================
--- libibverbs/ChangeLog	(revision 5421)
+++ libibverbs/ChangeLog	(working copy)
@@ -1,3 +1,11 @@
+2006-02-15  Roland Dreier  <rdreier at cisco.com>
+
+	* src/cmd.c (ibv_cmd_create_qp): Allow userspace device-specific
+	driver to pass in a response buffer, so that the low-level driver
+	in the kernel can pass back device-specific information.  This
+	changes the userspace driver API, since the signature of
+	ibv_cmd_create_qp() is changed.
+
 2006-02-14  Roland Dreier  <rdreier at cisco.com>
 
 	* Release version 1.0-rc6.
Index: libibverbs/src/cmd.c
===================================================================
--- libibverbs/src/cmd.c	(revision 5421)
+++ libibverbs/src/cmd.c	(working copy)
@@ -543,17 +543,11 @@ int ibv_cmd_destroy_srq(struct ibv_srq *
 
 int ibv_cmd_create_qp(struct ibv_pd *pd,
 		      struct ibv_qp *qp, struct ibv_qp_init_attr *attr,
-		      struct ibv_create_qp *cmd, size_t cmd_size)
+		      struct ibv_create_qp *cmd, size_t cmd_size,
+		      struct ibv_create_qp_resp *resp, size_t resp_size)
 {
-	union {
-		struct ibv_create_qp_resp    resp;
-		struct ibv_create_qp_resp_v3 resp_v3;
-	} r;
-
-	if (abi_ver > 3)
-		IBV_INIT_CMD_RESP(cmd, cmd_size, CREATE_QP, &r.resp, sizeof r.resp);
-	else
-		IBV_INIT_CMD_RESP(cmd, cmd_size, CREATE_QP, &r.resp_v3, sizeof r.resp_v3);
+	IBV_INIT_CMD_RESP(cmd, cmd_size, CREATE_QP, resp, resp_size);
+
 	cmd->user_handle     = (uintptr_t) qp;
 	cmd->pd_handle 	     = pd->handle;
 	cmd->send_cq_handle  = attr->send_cq->handle;
@@ -572,16 +566,22 @@ int ibv_cmd_create_qp(struct ibv_pd *pd,
 		return errno;
 
 	if (abi_ver > 3) {
-		qp->handle 		  = r.resp.qp_handle;
-		qp->qp_num 		  = r.resp.qpn;
-		attr->cap.max_recv_sge    = r.resp.max_recv_sge;
-		attr->cap.max_send_sge    = r.resp.max_send_sge;
-		attr->cap.max_recv_wr     = r.resp.max_recv_wr;
-		attr->cap.max_send_wr     = r.resp.max_send_wr;
-		attr->cap.max_inline_data = r.resp.max_inline_data;
+		qp->handle 		  = resp->qp_handle;
+		qp->qp_num 		  = resp->qpn;
+		attr->cap.max_recv_sge    = resp->max_recv_sge;
+		attr->cap.max_send_sge    = resp->max_send_sge;
+		attr->cap.max_recv_wr     = resp->max_recv_wr;
+		attr->cap.max_send_wr     = resp->max_send_wr;
+		attr->cap.max_inline_data = resp->max_inline_data;
 	} else {
-		qp->handle  = r.resp_v3.qp_handle;
-		qp->qp_num  = r.resp_v3.qpn;
+		struct ibv_create_qp_resp_v3 *resp_v3 =
+			(struct ibv_create_qp_resp_v3 *) resp;
+
+		qp->handle = resp_v3->qp_handle;
+		qp->qp_num = resp_v3->qpn;
+		memmove((void *) resp + sizeof *resp,
+			(void *) resp_v3 + sizeof *resp_v3,
+			resp_size - sizeof *resp);
 	}
 
 	return 0;